It’s no secret that eggs, full of protein, vitamins, and minerals (enough to grow a baby chicken from just one cell) are one of the most nutritious foods on the planet. Worldwide an average person consumes about 150 to 200 eggs annually. That’s over a trillion eggs per year! Now ask yourself this: “What happens to all of those eggshells?”
The calcium from eggshells is also welcome in garden soil, where it moderates soil acidity while providing nutrients for plants. Eggshells contain such an abundance of calcium that they can be used almost like lime, though you would need a lot of eggshells to make a measurable impact.
Yet eggshells are quite useful in adding calcium to homemade fertilizers, or you can simply make calcium water by steeping dried eggshells in water for a couple of days, and then using the strained water for your plants, including houseplants. Plants that haven’t been repotted for some time often perk up quickly when given a good drench of eggshell water.
Clean Eggshells are Safe Eggshells
Eggs are known carriers of salmonella, which should not be present on uncracked eggs that have been well washed, but you never know. Unless the only place the eggshells are going is into the compost bucket, I rinse them well and let them dry in a sunny windowsill.
The dryness should kill any salmonella present, but if you want to store ground eggshells that are safe for you or your dogs to eat (eggshell powder is used as a calcium supplement for dogs, too), sterilize them in a 200°F (93°C) oven for 30 minutes. You can then pulverize the dried eggshells using a mortar and pestle, or let a coffee grinder do the work for you. Stored in an airtight container, crushed eggshells will probably last forever.